Mechanical nut and stud removal tool

ABSTRACT

The invention concerns a tool for removing fastening members, such as nuts and studs. The tool comprises an elongate body member ( 30 ) with first and second ends, the first end having means ( 31 ′) for deforming an end face of the fastening member to provide an area of purchase thereon; and means ( 44 ) to cause rotation of the fastening member to unscrew the fastening member from the structure. Also within the scope of the present invention is a locating means ( 38 ′) for locating the first end of the body member ( 30 ′) with respect to the end face of the fastening member as well as a method for enabling removal of fastening members by action upon an end face of a fastening member.

The invention relates to a tool for removing fastening members, inparticular to a tool for removing nuts and studs.

Conventionally, nuts or studs would be removed by moving a spanner or awrench which acts upon the side face of the nut or stud to cause itsrotation. However, where the nut or stud has become damaged by its edgeshaving become “rounded”, it may be difficult to remove using the normaltools available. Also, in cases where nuts for instance have becomeseized, removal is problematic.

Existing methods for removing seized or damaged fastening members insuch conditions involve drilling, burning or cutting the fasteningmember in question from the object to which they are attached.

Another problem which is often encountered concerns situations in whichlocking nuts have been used, but the specialized tool for unlocking ofthe nuts is not available.

In a common field of application, vehicles with alloy wheels utilizelocking wheel nuts to prevent their theft. However, often the vehicleowner will not have the key or tool available in the event of abreakdown, for instance, after sustaining a flat tyre. Breakdownengineers called out to the scene often have very little option otherthan to tow the vehicle to a garage where further attempts would be madeto remove the vehicle wheel in question. However, attempts at removalwithout the proper key or tool (which may well be for all practicalpurposes unique to the particular vehicle on which the alloy wheels arefitted) often result in damage to the wheel and add considerable timeand expense to the repairs.

It will be appreciated that in the case of locking wheel nuts and in thecase of seized or damaged fastening members in other situations, it maybe only the end face of the particular fastening member which isaccessible so that getting a good grip around the circumference of thefastening member is not a viable option.

In such cases, being able to only access the end face exacerbates theproblem. Indeed, in the case of locking wheel nuts in particular thereis often an outer shell which is arranged to be freely rotating withrespect to a concealed and protected member underneath and in thosecases attacking the outer shell using hammer and chisel etc orattempting to drill into the wheel nuts often results in the chisel faceor the drill bit skating across the locking wheel nut and damaging thevaluable alloy wheels.

It is an aim of preferred embodiments of the present invention toprovide a tool for aiding the removal of fastening members which avoids,or alleviates to at least some extent, at least one of the problemsdescribed above in relation to the prior art.

According to a first aspect of the invention, there is provided a toolfor aiding the removal of a fastening member from a structure to whichit is attached by means of a threaded connection, the tool comprising:an elongate body member having first and second ends, the first endhaving means for deforming an end face of the fastening member toprovide an area of purchase thereon; and

means to cause rotation of the fastening member to unscrew the fasteningmember from the structure.

The fastening member may comprise a nut or stud.

Preferably, said means to cause rotation comprise attachment means forthe attachment of an operating member. The attachment means ispreferably located at the second end of the body member.

The attachment means may comprise a standard connection, such as a halfinch square drive in the form or a male or female connection. Otherstandard or specialised connections may alternatively be employed ofcourse.

The operating member may comprise an impact means such as an impactdriver for both imparting a blow to the tool and providing the means forrotation. An impact driver may be provided with the tool as anintegrated package.

It is also within the scope of the invention that a first operatingmember may be linked to the tool by way of the attachment means in afirst step so as to provide an impact to the tool, and a second,different operating member may be connected to the attachment meansduring a second step for providing said rotation. The first operatingmeans may comprise a bar or similar for receiving a blow from a hammer,and the second operating member may comprise, for instance, a wheelbrace.

The means for deforming the fastening member may comprise at least onecutting means such as a blade or a blade ring having blades arrangedaround an aperture formed in the blade ring for biting into said endface. The blade may be demountably attached to the elongate body. Theblade may include an angled cutting edge. The tool may include means forsecuring the blade to the elongate body, such as by grub screws. Theblade may be handed, so as to be orientable in a first configuration foruse with fastening members having a right hand threaded attachment, andto be orientable in a second configuration for use with fasteningmembers having a left-handed threaded attachment.

The first end of the body member may be provided with an aperturerunning longitudinally through the centre of the body member. Theaperture may run part way through the body member or it may run entirelythrough the body member. The aperture may couple with the attachmentmeans of the second end. The first end may comprise, in such a way thatit forms the attachment means, at least one blade. Preferably twoblades, are provided on either side of the aperture. The aperture mayenable a bolt or similar object, on which is threaded a fasteningmember, to be lowered into the body member such that the blades comeinto contact with an end face of said fastening member.

When situated within the body member, the bolt may form part of theattachment means.

It is another aim of certain embodiments to include some means forlocating the first end of the body member with respect to the end faceof the fastening member.

With a view to fulfilling the above aim, the tool is preferably providedwith locating means to locate the first end with respect to the end faceof the fastening member.

The locating means may comprise centralising means.

The locating means may comprise a mandrel for engagement with the endface of the fastening member.

The mandrel may be spring mounted within the body member.

The mandrel may be of male or female type.

Preferably the leading end of the mandrel is tapered.

According to another preferred feature of the invention, the tool isprovided with means for preventing peripheral damage to the structure.

For example a cover or shroud may be provided to surround the means fordeforming the end face of the fastening member.

According to a second aspect of the invention, there is provided amethod for facilitating the removal of a fastening member from astructure to which it is attached by means of a threaded connection, themethod comprising:

deforming an exposed end face of the fastening member to provide an areaof purchase thereon; and

rotating the fastening member using said area of purchase.

The method of the second aspect may include any one or more of thelimiting features of the apparatus of the first aspect in anycombination. The method may include the preliminary step of locating afirst end of the tool with respect to the end face of the fasteningmember. This locating step preferably includes the use of the locatingmeans.

Preferred embodiments of the invention will now be described withreference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a tool according to a first embodimentof the invention;

FIG. 2 is an end view of the first embodiment shown in FIG. 1;

FIG. 3 is a cross-sectional view through the line A—A of the firstembodiment shown in FIG. 1;

FIG. 4 is an end view of a tool according to a second embodiment of theinvention;

FIG. 5 is a side elevational view partially in cross-section of thesecond embodiment of the invention as shown in FIG. 4;

FIGS. 6A and B show an exemplary formation of a blade of the tool ofFIGS. 4 and 5 in side elevation and front elevation respectively;

FIG. 7 is a diagrammatic exploded view of an embodiment of the inventionincluding a locating means for locating the tool on an end face of thefastening member; and

FIGS. 8, 9, 10 and 11 are exploded perspective views of three furtherembodiments of the invention.

Referring to FIGS. 1 to 3, in the first embodiments of the invention,there is provided a tool comprising an elongate body member 10 having afirst end 12 and a second end 16.

The first end 12 includes a cutting blade 14, connected to the elongatebody 10 by means of grub screws 20.

The second end 16 contains a standard connection means 18, such as ahalf inch square drive connection, to which an impact driver or othersuitable operating member may be attached, as best illustrated in FIG.2.

In use, the blade 14 is placed into contact with the exposed end face ofthe fastening member to be released.

The second end 16 of the body member 10 is impacted by suitable means,such as by striking the end of an attached impact driver with a hammer.The impact causes the blade 14 to deform the end face of the fasteningmember, by biting into that end face and, in the case where thefastening member is a locking wheel nut having an outer shell and aninner nut, to cause the outer shell to lock with the inner nut.

Immediately after impact, the action of the impact driver causesrotation of the body member 10 which imparts rotational movement via theblade 14 to the fastening member.

Whilst it will be appreciated that some other operating means may beused to cooperate with the tool—for instance, a hammer could be firstused to cause the deforming and a wheel brace could then be attached tothe tool to provide the rotation—the use of an impact driver is mostpreferred. The reason that an impact driver is most preferred in thepresent invention is that during the imparting of the rotational force,the blade is further positively engaged with the deformed end face ofthe fastening member so as to provide extra security in use and greatlyfacilitate removal.

Referring now to FIGS. 4 and 5, a second embodiment of the invention isshown in plan view and side view (in direction CL of FIG. 4)respectively, with hidden detail shown by hatched lines (-----). Thisembodiment is particularly useful for removing a deformed or seized nutfastened to a bolt. The tool is generally similar to that shown in FIGS.1 to 3 and points of similarity designated by like reference numeralswill not be discussed further. However, the first end 12 of the toolincorporates a pair of blades 14A, B which are connected to the bodymember 10 by grub screws 20, running in threaded bores 21 and the twoblades are separated by a gap 22 formed by an aperture running throughthe body member 10. This aperture or cavity 22 runs longitudinallythrough the body member and is centrally located along the desired axisof rotation.

FIGS. 6A and B show a typical blade 14 formation. It will be appreciatedthat the blade 14 has an angled cutting edge 141 which is arranged, inuse, to bite into the end face of the fastening member to be deformedand a flat face 142, generally arranged in use to be at 90° to the endface of the fastening member. The angled face 141 in this way makes thedeformation in the fastening member and the flat face is arranged toimpart the rotational movement from the tools to the fastening member.The blade is “handed” in this way such that if the pair of blades 14A, Bwere fixed to the tool in the manner shown in FIGS. 4 and 5 then thedirection of loosening is shown by Arrow “A”. Loosening in this manneris brought about by the flat face 142 driving the fastening member. Tocope with both left and right handed threads, the blade 14 may beremoved and turned around such that the flat face 142 which includes a(optional) recess 143 for location of the grub screw 20, is alwaysarranged to drive the rotation of the fastening member during aloosening operation.

In use, the tool of FIGS. 4 and 5 is positioned such that the cavity 22receives the threaded end of a bolt or stud, to which the fasteningmember desired to be removed, is attached. The fastening member whichwill be assumed hereinafter to be a nut is brought into contact with theblades 14 by lowering the tool down the length of the bolt thread untilthe blades 14 engage with the end face of the nut.

Removal or loosening of the nut is then carried out in the same way asmentioned earlier, i.e. by imparting a blow to the second end of thetool 10 and rotating the tool to cause unscrewing of the nut from thebolt.

It will be appreciated that the cavity 22 may run throughout the lengthof the tool 10 and may, in itself, also form the means for connecting animpact driver. In otherwords, the aperture 22 need not be circular, butcould adopt a complimentary formation to that of the particular drivemeans being utilised to facilitate operation.

Although two blades are shown in the embodiment of FIGS. 4 and 5, and asingle blade shown in the embodiment of FIGS. 1 to 3, it will beappreciated that different numbers of blades may be utilised asrequired.

Referring now to FIG. 7, there will be described a locating means andmethod for locating the tool on the end face of the fastening member. Aswith other embodiments of the invention, the tool shown in FIG. 7 has abody member 30 which in use is fitted with blades 31. The blades 31 havea rib 32 which fits into a slot 33 extending across the body member 30.

The body member 30 has a passage 34 extending therethrough and withinthis passage there is a web 35 having a central aperture 36.

The lower end of the passageway 34 receives a compression spring 37 anda mandrel 38. The compression spring 37 acts between the mandrel and theweb 35. The mandrel 38 is retained in position by a bolt 39 which passesthrough the hole 36 in the web 35 and into a threaded bore 40 in themandrel 38. The leading end 41 of the mandrel is tapered.

When the tool is presented to the end face of the screw threaded memberto be removed, the tapered end 41 of the mandrel 38 is projecting beyondthe blades 31, since there is also a passageway 42 through the bladedmember.

Thus, the leading end of the mandrel 38 may first be adjusted until itis in the exact centre of the exposed end face of the threaded memberbefore an impact is delivered to drive the blades into the end face.

When the blades are driven into the end face, the mandrel 38 isdepressed further into the body member 30 against the action of thespring 37.

To reduce the risk of peripheral damage to the surrounding structurecontaining the threaded member which is to be removed, the whole tool isprovided with a cylindrical sleeve 43 to capture any debris from theblades and prevent this debris from reaching the surrounding structure.

The upper part of the passageway 34 may have a square cross section, sothat a square key can be inserted into it to provide rotational movementto the tool.

The invention is not restricted to the features of the foregoingembodiment. For example, male and female members may be reversed. Forexample instead of using a male mandrel which fits into a socket in thebody, a female mandrel could be provided which slides over a projectingpart of the body.

FIGS. 8 to 10 show further embodiments of the invention. Where there arepresented like elements to those shown in FIG. 7, the same referencenumbers will be utilized together with a prime (′), double prime (″) ortriple prime (′″).

The embodiment of FIG. 8 is broadly similar to the embodiment of FIG. 7aside from the fact that mandrel 38′ is arranged such that the spring37′ locates within passageway 34 (not shown in this Figure) of the bodymember 30′ with the enlarged head 38A having the free end of the spring37′ acting upon it so as to tend to keep the mandrel 38′ in a positionin which the tapered head 41′ remains protruded beyond the end of bladering 31′. A blade ring 31′ is maintained in position in relation to bodymember 30′ by means of the cooperating rib 32′ and slot 33′, these twoelements being kept in association with one another by means of a splitring 33A. On FIG. 8, and also shown in FIGS. 9 and 10, there is furtherprovided an O ring 30A against which an end portion of shroud 43′ isarranged to seat. Further, there is shown in each of FIGS. 8 to 10 animpact bar 44 having a square peg connection 44A for cooperation, inuse, with the upper part of passageway 34 which, as discussed already,is of square cross-section.

The main variation between the embodiment of FIG. 8 and FIG. 9, is thatthe embodiment of FIG. 9 does include a bolt 39″ in similar fashion tothe bolt 39 of FIG. 7. The bolt 39″ cooperates with a threaded apertureformed in the mandrel 38″. The mandrel 38″ is of generally enlargedproportions as compared with the mandrel 38′.

The embodiment of FIG. 10, is most similar to the embodiment shown inFIG. 8 and differs simply by the mandrel 38′″ being of enlargedproportions as compared to the mandrel 38′.

FIG. 11 is an exploded view showing the various differentinterchangeable parts as referred to previously which path for use withthe tool. In addition, FIG. 11 shows (at reference numeral 45) a plasticshroud which assists in centralising the tool when using the bladesshown as 31′″ and 31′. It further shows, a centre punch 50 which can beutilised prior to using the tool to mark a centre point on a fasteningmember which is to be loosened.

It will be appreciated that various modifications may be made to theembodiments of the present invention whilst remaining within the scopeof the invention. For instance, the invention includes embodiments ofthe tool incorporating integral impact driver portions as well asembodiments requiring the use of an external impact driver andembodiments which may use other means of engagement.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

All of the features disclosed in this specification (including anyaccompanying claims, abstract and drawings), and/or all of the steps ofany method or process so disclosed, may be combined in any combination,except combinations where at least some of such features and/or stepsare mutually exclusive.

Each feature disclosed in this specification (including any accompanyingclaims, abstract and drawings), may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

The invention is not restricted to the details of the foregoingembodiment(s). The invention extends to any novel one, or any novelcombination, of the features disclosed in this specification (includingany accompanying claims, abstract and drawings), or to any novel one, orany novel combination, of the steps of any method or process sodisclosed.

What is claimed is:
 1. A tool for aiding the removal of a fasteningmember from a structure to which it is attached by means of a threadedconnection, the tool comprising: an elongate body member (30) havingfirst and second ends, the first ends having means (31) for deforming anend face of the fastening member to provide an area of purchase thereon;and means (44) to cause rotation of the fastening member to unscrew thefastening member from the structure, the tool being characterized inthat a mandrel (38) is provided which is spring mounted within the bodymember and arranged to engage with the end face of the fastening memberfor locating the first end of the body member with respect to the endface of the fastening member.
 2. A tool according to claim 1, whereinsaid means to cause rotation comprises attachment means for theattachment of an operating member (44) and wherein the attachment meansis located at the second end of the body member (30).
 3. A toolaccording to claim 2, wherein the means to cause rotation furthercomprises an impact means.
 4. A tool according to claim 1, wherein themeans for deforming the fastening member comprises at least one cuttingmeans (31′) for biting into said end face.
 5. A tool according to claim4, wherein the cutting means includes at least one angled cutting edge.6. A tool according to claim 4, wherein the cutting means comprises ablade ring (31) having blades arranged around an aperture formed in theblade ring.
 7. A tool according to claim 1, wherein the first end of thebody member is provided with an aperture running longitudinally throughthe center of the body member.
 8. A tool according to claim 6, whereinthe aperture enables a bolt or similar object, on which is threaded afastening member, to be lowered into the body member such that theblades (14, 31) come into contact with an end face of said fasteningmember.
 9. A tool according to claim 1, wherein the leading end of themandrel (38) is tapered.
 10. A tool according to claim 1, wherein thetool is provided with means (43) for preventing peripheral damage to thestructure.
 11. The tool according to claim 10, wherein a cover or shroud(43) is provided to surround the means for deforming the end face of thefastening member.